_ Evapora- 
~ tion. 
e ; 
EVA 
ration; or‘evén gained @ sinall addition to its weight, 
as part ofthe moisture which evaporated from the sur- 
face of the ground might have been condensed over the 
“Dr Wells: mentions, on the authority of cet a 
and Mr Williams, both of pc testers mo 
process in India, that; for the complete success ; 
experiment, it is necessary the air should be very still; ~ 
and he adds, that “wind, which so greatly promotes 
evaporation, prevents the freezing altogether,” without 
seeming to be aware, that this fact is still more irrecon- 
cileable with his own hy is, it being well known, 
that radiation is not affected by a transverse current of 
, DUE, prone. carmen. wes » that evaporation is 
the cause of the ction of temperature, a rea- 
may assigned vhy agitated state 
Scedlplisonisinecg trie tation Guaoeapeeclinn 
No reason can be given, 
pals. 
radiation, the congelation succeeds 
sebunaphalbierdiediass but, on 
ge 
is of Dr Wells, we 
sed to say, that radiation has no share in the effect, or, 
attention to accuracy, 
are still necessary for the 
full elucidation of the subject. : 3 
as much as possible, without the cy of heat : Thus 
the form, as well as the colour of delicate plants, upon 
poo com le ere in the preserved state 
depends, woul ina measure d ed 
exposing them to Geathiais of ew thoved It bab theatre 
been proposed, to dry them in an exhausted: receiver, 
by suspending them over a vessel containing sulphue 
ric acid, the muriate of lime, or any other substance 
which has a attraction for humidity, and allow- 
ing them to remain in ‘that situation, until the whole * 
of their moisture was’ 
says On » Murray’s Chemistry, vol, ii. 
705. » Dr’ «ute (a) i ee 
~ EUCALYPTUS. See Botany, p. 229. " 
T A223 1 
EUC 
EUCERA. ‘See Entomonocy Index. 
EUCLASE. See Oryeroenosy. 
EUCLEA. See Borany, p. 337. 
- EUCLID, the Mathematician, was born at Alexan- 
dria in Egypt, about 300 years before Christ. We 
have no certain information as to the precise period, 
either of his birth or death; - come Lada ry 
particulars respecting his life. It would appear that he 
resided constantly ae his native city, and devoted him- 
self to the study of the mathematics, which he culti« 
vated and taught with distinguished success. Among 
his scholars, he had the honour of ceakeving Ptolemy 
Philadelphus, King of Egypt, of whom us relates 
an anecdote, w thy of being ed, not only as it 
shews the friendship and iarity which Euclid en-~ 
joyed with his royal pupil, but as it is strikingly cha- 
racteristic of an enthusiastic geometer, and the only one 
on record which brings him, as it were, personally be- 
fore us. Ptolemy, fatigued with the long and unre- 
mitting attention necessary to comprehend the demon- 
strations of certain itions, one day inquired of 
his teacher whether he could not point out an easier 
method of investigation? ‘No, sire,” replied the phi- 
losopher, ingenuously, “ there is no royal road to geo- 
metry. 
“The work by which Euclid is best known to us, is 
his Elements ; a work which, to use the words of a 
which there is refinement enough for the expression of 
abstract truth.” Various opini however, have been 
entertained with regard to the share which Euclid had 
in the composition of these Elements, While some main- 
tain that he was the author of the whole, others assert 
that the demonstrations only are his, and others that he 
furnished the propositions alone. As in most disputes 
ofthis kind, none of the contending parties are per- 
fectly correct. Independent of the undeniable. 
that some i propositions were furnished by 
others, as the 47th of the first book, by Pythagoras, it 
must be obvious, from the state of the mathematical 
sciences at the period in which Euclid wrote, that he 
could not be theauthor of the whole. Long before his 
time, mathematicians had been 
to solve the famous problems of the duplication of the 
cube, and the trisection of an angle, problems which 
they never could have attempted without the assistance 
of many propositions to be found in his Elements, On 
the other hand, it seems impossible to grant; what is 
universally allowed, that he was the first who arran- 
ged all the propositions»then known into a system, 
without ting a great deal more. The mind that 
mebaspibteiad putting such a system together, even 
the materials had been ready furnished, could 
'y fail to discover some room for improvement,— 
some defect to be supplied; or some weak: link that rey 
quired to be strengthened. Reasoning, then, from 
what we might naturally suppose to be the process of 
a mind accustomed to scientific investigation, we shall 
be led to conclude that Euclid must have been the au- 
thor of no inconsiderable part of the Elements, «This 
Socematy to cutie him tothe appellasoa of tha Rather 
to entitle him to the ap ion e 
of Geometry. \ Even supposing every proposition in the 
Elements to have been wn and demonstrated, still 
they were but insulated truths, and; as such, of com+ 
ively little value. ‘The young mathematician, un- 
he possessed no ordinary portion of ingenuity, 
in attempting - 
Euclid. 
